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The Planets this Month - January 2014

Mercury

Mercury reaches greatest elongation east on January 31st and is visible as an evening object for observers during the later half of the month. For Northern Hemisphere observers, this is the most favourable evening apparition of the year and therefore the best chance in 2014 to catch a glimpse of this illusive world after sunset. From the Southern Hemisphere, Mercury is not well placed but observers may still be able to spot the planet extremely low down just after sunset at the end of the month.

From northern temperate latitudes, the planet should be visible above the southwestern horizon from about January 20th until the first week of February. During this time Mercury climbs higher and higher in the evening sky until January 31st, the date of greatest elongation east. On this day, Mercury is positioned 18 degrees east of the Sun. For example from London, England (51.5N), Mercury appears about 10 degrees above the horizon, 45 minutes after sunset and shines at magnitude -0.7. Before this date, Mercury will be brighter and theoretically easier to locate, but on the other hand closer to the horizon. The illuminated phase of Mercury decreases from 90 percent on January 19th to 55 percent on January 31st.

The planet remains visible into the first week of February but more difficult to detect as it fades quickly in brightness.

Venus

The long evening apparition of Venus reaches an end at the beginning of January. During the first few days of the month, the planet remains visible as a dazzling beacon low down towards the west-southwestern horizon just after sunset. At magnitude -4.3, it's unmistakable due to its brilliance. It displays a very thin crescent phase of only 3 degrees with a large apparent size of about 60 arc seconds. A few days later on January 11th, this evening apparition draws to a close as Venus reaches inferior conjunction.

However, it's not long before Venus re-appears in the morning sky. From about January 18th, it should be possible to spot the planet in the pre-dawn sky when it appears a few degrees above the horizon just before sunrise. At the end of the month it's much easier to catch Venus when it's higher in the sky with a magnitude of -4.6, apparent size of 51 arc seconds and illuminated phase of 12 percent.

On January 24th, Venus reaches perihelion at 0.718 AU (approx. 107 million km or 66.7 million miles) from the Sun and on January 29th, the waning crescent Moon passes 2 degrees south of Venus.

Mars

Mars continues to gain in brilliance and apparent size as it heads towards opposition in April. The planet continues direct motion through Virgo, increasing from magnitude +0.8 on January 1st to magnitude +0.3 on January 31st. During this time period, it's apparent size increases from just below 7 arc seconds to nearly 9 arc seconds.

Now rising around midnight, it's possible to start serious telescopic observations of the famous "Red planet". However, the apparent size is small compared to that of Jupiter and Saturn and hence requires good seeing, high magnifications and preferably at least a medium sized (200mm - 8 inch) telescope to make out prominent markings.

On January 3rd, Mars reaches aphelion and is located 1.666 AU (approx. 249.2 million km or 154.9 million miles) from the Sun. Later in the month (Jan. 23rd), the waning gibbous Moon passes 4 degrees south of Mars and five days later on January 28th, Mars passes 5 degrees north of Spica (α Vir - mag +1.0), the brightest star in Virgo.

Jupiter reaches opposition on January 5th and is visible all night, rising in the east when the Sun sets and setting when the Sun rises the following morning. At magnitude -2.7, the largest of all planets in the Solar System is a dazzling sight, dominating the night sky as it moves retrograde amongst the stars of Gemini.

This year at opposition, Jupiter is located 4.21 AU (629.87 million kilometers or 391.38 million miles) from Earth which corresponds to an apparent size of 47 arc seconds. The planets current declination of +23 degrees favours Northern Hemisphere observers where Jupiter appears higher in the night sky with a longer period of visibility. For those at southern latitudes, the planet appears lower down and much closer to the horizon, but still unmistakable due to its brilliance.

A pair of binoculars will reveal the planets disk, appearing creamy off-white in colour although very small. Also visible are Io, Europa, Ganymede and Callisto, the four large Galilean moons. As they orbit Jupiter they are constantly changing position and sometimes all four are visible, but on other occasions some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.

When viewed through a telescope, Jupiter is an awesome sight. A 80mm (3.1 inch) telescope shows the main northern and southern equatorial cloud belts and other finer details along with the Galilean moons. Larger telescopes reveal much more including smaller belts, ovals, festoons, darkenings and of course the famous "Red Spot".

Saturn is now an early morning object visible towards the east-southeast. It's currently located amongst the stars of mid-Libra. At the beginning of the month Saturn rises about 4 hours before the Sun from northern temperate latitudes and only slightly less from locations further south. By months end the planet rises some 6 hours before the Sun.

Saturn shines at magnitude +0.8 during January with an apparent size of about 16 arc seconds. On January 25th, the last quarter Moon passes 0.6 degrees south of Saturn. An occultation is visible from New Zealand and the southern tip of South America at 13:58 UT.

Uranus

Uranus is located in Pisces and moving direct just southeast of the "Great Square of Pegasus". The planet is visible during the first half of the night but sets before midnight.

At magnitude +5.9, Uranus is a very easy binocular or small telescope target. Although its relatively easy with high powers to show the disk of Uranus, the apparent size is only 3.5 arc seconds and hence spotting any surface details is difficult even with the largest amateur telescopes.

On January 7th, the first quarter Moon passes 3 degrees north of Uranus.

Neptune, mag. +8.0, is visible as soon as it's dark enough for a short time after sunset during the first part of January. This represents the last chance to catch a glimpse of the most distant planet before it reaches solar conjunction in February. As the month progresses it will become increasing more difficult to spot the dim planet before its lost to the twilight sky.

Neptune is located in Aquarius and positioned almost 3 degrees west of Sigma (σ) Aqr (mag. +4.8) and 3 degrees south of Ancha (θ Aqr - mag. +4.2).

On January 5th, the waxing crescent Moon passes 5 degrees north of Neptune.